a) Field of the Invention
The invention is directed to a device for coupling containers at a loading and unloading port with a horizontally displaceable platform for receiving the container, means for orientation and fastening of the container on the platform, and with a removable closure in the loading and unloading port.
b) Description of the Related Art
For containers used for transporting large objects in the fabrication of integrated circuits, it is known from DE 195 42 646 A1 to deposit these containers on a platform. Alignment elements formed as grooves and as pins engaging in the grooves are usually provided as orientation means in the base of the container and in the platform, wherein these alignment elements are arranged in a three-point formation so as to match one another. For purposes of fixing the container, it is known, on the one hand, to let a beveled peg fastened to the container base at a distance therefrom slide below a stationary contact-pressing arm. On the other hand, a key that is guided through a bore hole in the platform can also be provided. When the transport container is placed on the platform, it penetrates through a keyhole incorporated in a plate fastened at a distance from the container bottom and engages behind this plate after a closing movement.
The latter step has the disadvantage that greater degrees of freedom in orientation, which are often demanded, do not allow for fastening, although the widening of the keyhole is subjected to limitations.
A further disadvantage in the known device consists in that protection against errors when charging the platform with containers can sometimes not be adequately ensured. When the containers are transported and transferred by automatic systems, collisions must be excluded.
It is the primary object of the invention to increase protection against faulty operation and faulty loading in a simple manner while guaranteeing technical cleanroom requirements without limiting the clear space of the platform.
According to the invention, this object is met by a device for coupling containers at a loading and unloading port with a horizontally displaceable platform for receiving the container, means for aligning and fastening the container on the platform, and with a removable closure in the loading and unloading port, in that means for detecting the presence of a container and for distinguishing between containers with different contents are provided for an expectancy area above the platform.
The presence of a container is detected in that at least one reflector is provided at least in the vicinity of the loading and unloading port, which reflector directs a beam of at least one transmitter penetrating the expectancy area for the container to at least one receiver. The reflector can be arranged at the closure as well as at the wall element.
The presence of a container can also be detected in that there is provided at least in the vicinity of the loading and unloading port at least one receiver for receiving a beam of a transmitter which penetrates the expectancy area for the container. Like the reflector, the receiver can also be arranged at the closure or at the wall element.
In order to distinguish between containers, the platform has at least one protruding area which enables a reference position on the alignment means in a container suitable for coupling in that these means engage in matching recesses in the base of the container. In a container that is not suitable for coupling, the protruding area causes a deviation from the aligned reference position through the absence of the recess. A sensor below the platform can distinguish between the different distances of the container base from the platform through a window in the platform by means of a distance-selective detection area.
The reflector advantageously has, at the closure, metallically reflecting surfaces which change the polarizing direction of polarized initial or output radiation. Every receiver is suitable only for reception of a beam altered in this way.
It is further advantageous when retaining elements are provided below the platform, which retaining elements project through an opening in the central area of the platform for fastening the container to the platform and grasp the container. Two latches which are adjustable in opposite directions relative to one another about axes of rotation by means of a crank serve as retaining elements.
A hindering of the freedom of movement is ruled out due to the fact that the latches are located below the platform during the advancing feed of the container.